As is known in the art, medical imaging, such as MRI, CT and ultrasound have been used to detect a biopsy device that is inserted into tissue of a patient. More particularly, needle-like devices are introduced through the skin, through small orifices into the body of the patient during medical interventional procedures. The instruments are guided only according to “feel” or with the aid of an imaging diagnostic device, preferably with the aid of a tomography device or ultrasound.
In methods of the above type, the position of a slice of the body of the patient shown in a reconstructed image can be described, for example, by its position relative to the patient and its inclination relative to the longitudinal axis of the patient. These parameters should be selected such that the instrument, for example a puncture needle in a slice of the body of the patient shown in a tomogram, for example, can be guided to the desired object or site, for example to an organ of the patient. This task is difficult because: 1) the biopsy device is absent in most of the images; 2) the position and the orientation of the device may vary a lot among different studies; and 3) the signal strength at the device location can be very low.
One technique used to display the tip of a needle-like medical device is described in U.S. Pat. No. 6,529,766 entitled “Method for Displaying the Tip of a Medical Instrument Situated in the Body of a Patient, issued Mar. 4, 2003, inventor Lutz Guendel, assigned to the same assignees as the present invention. As described therein, the method displays the tip of a medical instrument situated in the body of a patient during a medical interventional procedure by means of an imaging method, including the steps of repeatedly acquiring data for a number of planar slices of the patient during the interventional procedure, subsequently analyzing the data to identify in which of the slices the tip of the instrument is situated, and generating a signal that marks the slice that contains the tip of the instrument. Only that slice that is identified by the signal produced by the tip of the instrument is reconstructed by means of the imaging method and is displayed at a display unit.
More particularly, as is known, each scan contains several slices that cover a volume. Among all the slices of one scan, the biopsy device is only present in typically at most three slices. Sometimes it only appears in a single slice. Therefore, the device may not appear in the first slice. When that happens, there is no way to obtain any useful information regarding the device based on the first slice. Thus, given a set of images of a number (5 to 11) of slices containing a biopsy device, the goal is to determine in which of the slices the biopsy device is situated and identify both the position and the orientation of the device in that slice. With this information, it is desired that the imaging plane of the next scan be automatically adjusted to be parallel to the biopsy device. Therefore, the biopsy needle and most importantly the tip of the needle can be clearly seen in the next scan.
In accordance with the present invention, a method is provided for detection of the position and orientation of the tip of a needle-like medical device inserted into a tissue of a patient using scanning apparatus, such method comprising: during an initial scan of the tissue with the apparatus, obtain several image slices through the tissue having therein the device, each one of the slices having a known orientation with respect to a reference co-ordinate system fixed with respect to the scanning apparatus; detecting the device in one of the slices obtained from the initial scan including identifying such one of the slices and the position and angular orientation of the device in such one of the slices; combining the identified one of the slices and the position and angular orientation of the device in such one of the slices with respect to the reference coordinate system of the scanning system to determine an appropriate imaging plane for a subsequent scan; repeating the process until a final slice is obtained having a predetermined degree of clarity of the entire needle-like device and with the needle-like device disposed in a known orientation with respect to the reference co-ordinate system; and identifying the tip of the device in the final slice.
In one embodiment, a method is provided for detection of the position and orientation of a needle-like medical device inserted into a tissue of a patient using scanning apparatus includes obtaining a first scan of the tissue correlating the needle-like medical device with a plurality of needle-like templates, each one of the templates having a different angular orientation to obtain an feature image of the device; thresholding the obtained feature image to obtain a binary image of the device; using connected component analysis (labeling) for candidate detection and using principal component analysis to obtain eigenvalues and eigenvectors of each candidate in the binary image; using the obtained eigenvalues and eigenvectors to detect the position and orientation of the device and therefore obtain the angular orientation of an image plane for a subsequent scan of the tissue.
In one embodiment, the method includes automatically determining the orientation of the image plane of the next scan having the device with a predetermined likelihood or greatest likelihood using the eigenvalues and the eigenvector associated with the largest eigenvalue obtained from a previous scan.
In one embodiment, position and orientation of the tip of the device is determined by a method comprising transforming the orientation of the device in the determined image plane into scanning system reference coordinates with the longitudinal axis of the needle like device having a predetermined orientations with respect to the reference coordinate system and making observations along each of a sequence of lines transverse to the longitudinal axis of the image of the device in the determined plane to detect the tip of the device.
In one embodiment, a method is provided for detection of the position and orientation a needle-like medical device inserted into a tissue of a patient using scanning apparatus. The method includes: obtaining in a first scan of the tissue, a plurality of slices of images having therein the medical device; for each one of the slices, determine eigenvalues and an eigenvector of an possible image of the device; and automatically determine the orientation of the image plane for a possible image of the medical device for a subsequent scan of the tissue using the eigenvector and eigenvalues of obtained from the first scan.
In one embodiment, the orientation of the image plane of the subsequent scan uses the eigenvalues of the first scan to determine the possible medical device images with a predetermined or greatest likelihood.
In one embodiment, a method is provided for detection of the position and orientation of the tip of a needle-like medical device inserted into a tissue of a patient using scanning apparatus. The method includes: obtaining in a first scan of the tissue, a plurality of slices of images having therein the medical device; for each one of the slices, determine eigenvalues and an eigenvector of an possible image of the device; automatically determine the orientation of the image plane for a possible image of the medical device for a subsequent scan of the tissue using the eigenvector and eigenvalues of obtained from the first scan; transforming the orientation of the image of the device in the subsequent scan into scanning system reference coordinates; and making observations along each of a plurality of lines transverse to the longitudinal axis of the image of the device in the scanning system reference system to detect the tip the device.
In one embodiment, a method is provided for detection of the position and orientation of the tip of a needle-like medical device inserted into a tissue of a patient using scanning apparatus. The method includes: obtaining a first scan of the tissue correlating the needle-like medical device with a plurality of needle-like templates, each one having a different angular orientation to obtain an feature image of the device; obtaining eigenvalues and an eigenvector of image to obtain the angular orientation of an image plane for a subsequent scan; transforms the orientation of the device in the determined image plane into scanning system reference coordinates with the longitudinal axis of the needle like device having a predetermined orientations with respect to the reference coordinate system; and making observations along each of a sequence of lines transverse to the longitudinal axis of the image of the device in the determined plane to detect the tip of the device.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.